Enhancement of resistance to bacterial infection in rainbow trout, Oncorhynchus mykiss (Walbaum), by oral administration of bovine lactoferrin

Abstract Bovine lactoferrin was evaluated for its ability to enhance resistance of rainbow trout, Oncorhynchus mykiss (Walbaum), to infection with Vibrio anguillarum. Oral administration of lactoferrin (100 mg kg⁻¹) to fish daily for 3 days prior to an intraperitoneal challenge with V. anguillarum resulted in increased survival rates, and enhanced resistance against Streptococcus sp., although to a lesser extent. In lactoferrin-treated fish, an increase in phagocytic and chemiluminescent (CL) activities of pronephros cells against V. anguillarum was observed. The phagocytic and CL activities of cells against Streptococcus sp. were also significantly increased. However, no in vitro bactericidal activities of lactoferrin against V. anguillarum or Streptococcus sp. were observed. This suggests that the lactoferrin enhanced the resistance of the rainbow trout against bacterial infection through the activation of phagocytes.     

Efficacy of specific antibody against agglutinating Aeromonas salmonicida strains on infectivity and vaccination with inactivated protease

Efficacy of specific antibody on serum resistance and adhesion was investigated using a pathogenic strain of Aeromonas salmonicida A-7301 (which was autoagglutinative, haemagglutinative and protease production positive), a protease-deficient, non-pathogenic mutant NTG-1 induced from A-7301 (autoagglutinative and haemagglutinative), and a non-pathogenic strain GH-7501 (non-agglutinative, non-haemagglutinative and protease positive). A-7301 could grow and produce protease extracellularly in the presence of rainbow trout anti-A-7301 serum, resulting in a considerable reduction of the antibody titre. NTG-1 similarly grew, but the titre scarcely decreased. GH-7501 could not survive in this medium. A-7301 and NTG-1 possessed a high capacity to adhere to the surface of fish monolayer cell cultures, whereas GH-7501 lacked the capacity. The capacity for adhesion was not inhibited by the antibody. Although live NTG-1 cells were ineffective as a live vaccine, sockeye salmon receiving protease fraction (obtained from extracellular products of A-7301 by DEAE-cellulose column chromatography) inactivated with normal serum, suffered only a low mortality when challenged with A-7301. Thus, although the antibody specific to autoagglutinating cells showed no effects on serum resistance and adhesion, which are involved in the infectivity of this pathogen, the possibility of protease as an effective protective antigen was demonstrated.     

Effects of the application of carbonaceous adsorbents on pumpkin (Cucurbita maxima) uptake of heptachlor epoxide in soil

The use of heptachlor, a cyclodiene-type insecticide, has been banned since the 1970s because of its carcinogenic potential. However, its metabolite, heptachlor exo -epoxide (HEPX), has still been detected in the fruit of cucurbits produced in some areas. It is important to reduce the daily intake of HEPX contained in food. To address this issue, the effects of carbonaceous adsorbents on the uptake of HEPX from the soil by Cucurbita maxima Dutch. (winter squash) were investigated. Amorphous organic carbons, such as peat moss and wood chips, did not affect the concentration of HEPX in the soil solution or the amount present in the shoots. In contrast, relatively condensed carbon, such as activated carbons, decreased the concentration of HEPX in the soil solution and in the shoots. The uptake amount in the shoot was closely correlated with the concentration of HEPX in the soil solution, which suggests that its uptake by C .  maxima depends on its concentration in the soil solution. Activated carbons did not affect the growth of C .  maxima . Therefore, the application of activated carbon to soil contaminated with HEPX appears to be an effective method of reducing the uptake of HEPX by C .  maxima .     

Production of transgenic cloned pigs expressing the far-red fluorescent protein monomeric Plum

Monomeric Plum (Plum), a far-red fluorescent protein with photostability and photopermeability, is potentially suitable for in vivo imaging and detection of fluorescence in body tissues. The aim of this study was to generate transgenic cloned pigs exhibiting systemic expression of Plum using somatic cell nuclear transfer (SCNT) technology. Nuclear donor cells for SCNT were obtained by introducing a Plum-expression vector driven by a combination of the cytomegalovirus early enhancer and chicken beta-actin promoter into porcine fetal fibroblasts (PFFs). The cleavage and blastocyst formation rates of reconstructed SCNT embryos were 81.0% (34/42) and 78.6% (33/42), respectively. At 36–37 days of gestation, three fetuses systemically expressing Plum were obtained from one recipient to which 103 SCNT embryos were transferred (3/103, 2.9%). For generation of offspring expressing Plum, rejuvenated PFFs were established from one cloned fetus and used as nuclear donor cells. Four cloned offspring and one stillborn cloned offspring were produced from one recipient to which 117 SCNT embryos were transferred (5/117, 4.3%). All offspring exhibited high levels of Plum fluorescence in blood cells, such as lymphocytes, monocytes and granulocytes. In addition, the skin, heart, kidney, pancreas, liver and spleen also exhibited Plum expression. These observations demonstrated that transfer of the Plum gene did not interfere with the development of porcine SCNT embryos and resulted in the successful generation of transgenic cloned pigs that systemically expressed Plum. This is the first report of the generation and characterization of transgenic cloned pigs expressing the far-red fluorescent protein Plum.     

Mixed germ cell-sex cord-stromal tumor with a concurrent interstitial cell tumor in a ferret

A 5-year-old male ferret presented with an enlarged canalicular testis in the left inguinal region. Microscopically, the enlarged testis consisted of a diffuse intimately admixed proliferation of c-kit-positive germ cell-like and Wilms tumor-1 protein-positive Sertoli cell-like components, but no Call-Exner body was detected. In addition, the compact proliferation of steroidogenic acute regulatory protein-intense positive interstitial cells was identified in a separate peripheral area of the mass. Based on histopathological and immunohistochemical findings, the tumor was diagnosed as a mixed germ cell-sex cord-stromal tumor with a concurrent interstitial cell tumor.     

Notes on the Occurrence of Pathogenic Races of <Emphasis Type="Italic">Xanthomonas oryzae </Emphasis>pv. <Emphasis Type="Italic">oryzae </Emphasis>Found in Hiroshima Prefecture in 1999

The pathogenic race of 59 cultures of Xanthomonas oryzae pv. oryzae, a pathogen of bacterial leaf blight of rice, isolated from six locations in the inland mountainous area of Hiroshima Prefecture in 1999, were determined by a set of traditional differentials. Four races—I, II, V and VII—were found across the area; however, we noticed the composition of the races as well as the dominant race in each location different. All races were avirulent on differential cultivar Te-tep. Races V and VII were new to Hiroshima. The rice cultivars infected with bacterial leaf blight in Hiroshima are thought to be grouped into the Kinmaze group, which does not have any resistance genes. Apparently, a variety of races occurred unexpectedly on the cultivars contrary to stabilizing selection theory. Received 25 February 2000/ Accepted in revised form 13 July 2000